Therapeutic humanized monoclonal antibodies (mAbs) are focused on as effective medicine owing to their high specificity and efficacy compared with conventional small-molecule pharmaceuticals. To avoid side effects, controlling the dose of therapeutic mAbs for the patient is the most crucial. However, the monitoring of their concentrations demands highly specific discrimination from human immunoglobulin G (IgG), since the most therapeutic mAbs are designed based on IgG, which is naturally present in large quantities in human blood and differs only in residues at the complementarity determining region (CDR). To solve this problem, our group developed an anti-idiotype therapeutic mAbs aptamer by systematic evolution of ligands by exponential enrichment (SELEX). As a representative therapeutic mAbs, we chose bevacizumab, which is a recombinant humanized monoclonal antibody that inhibits angiogenesis by binding to vascular endothelial growth factor (VEGF). The X-ray structure of obtained bevacizumab-aptamer complex revealed that the aptamer binds to CDR of bevacizumab and can distinguish bevacizumab and other IgGs. In this study, we developed an electrochemical sensor for bevacizumab using the redox-probe modified anti-idiotype bevacizumab aptamer. Using phenazine ethosulfate modified-aptamer with square wave voltammetry detection principle, bevacizumab was specifically detected with the concentration range 1 -100nM, without showing significant non-specific signal. These results demonstrated that monitoring of therapeutic mAb will be realized using redox probe modified anti-idiotype aptamer.

Development of the therapeutic humanized monoclonal antibody aptamer sensor

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ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.